Starting mechanism for internal-combustion engines



ISAAC THOMAS THORNYCROFT, USUALLY KNOWN AS TOM T HORNYCROFT.

STARTING MECHANISM FOR INTERNAL COMBUSTION ENGINES.

APmcATloN man No.9, 191s.

1.541423?,9 Patented Apr. 25, 1922,

3 SHEETS-SHEET l.

ISAAC THoMAsHoRNYcRoFT, ulsuALLY KNOWN As 10M IHORNYGBOFL- STARTING IIIECHANISM FOR INTERNAL COMBUSTION ENGINE-S;

APPLICATION FILED DEC.9, |918.

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ISAAC THOMAS THORNYCROFI, USUALLY KNOWN ASl IOM TIHORNYCROFT.

summe NEcHANlsN Foa INTERNAL coNBu'snoN ENGINES. I

. APPLICATION FILED DEC.9, |918. 1 j,414,2,"?,3 Patented Apr. 25, 1922.

3 sains-SHEET s.

Uris sie?? siem r f ISAAC THOMAS THoRNYcRorT, (USUALLYKNOWN As 'rom' THORNYCROFTJ or WwEsTMINsTER,' ENGLANn' f v sTARTiNG MECHANISM- non -Intra KNAL-coivn'aiisTIoNAV nive-iiinis;L

4To all/'whom t may concern.'

Be 1t known that I, ISAAC THOMAS THORNY- cizoFT, (usually known asl TOM THORNY- oRorT,) a subject of the King of Great Britain and Ireland, residing at` the city of Westminster, Ilngland,` have invented Improvements in or Relating to Starting Mechuanism for Internal-Combustion Engines, of

. ward direction.

The-present invention has reference to improved constructions of engine starting apparatus of the .typereferred to, as will now be described with 'theaid ofthe accompanyingv illustrativedrawings. j

In these drawings, Fig.'1 shows partly in elevation and partlyin longitudinal section, and Fig. 2 in plan,and^more or lessdiagrammatically, one construction'of engine starting mechanism accordingto the invention.

Fig. 3 is a cross section on ,the line AIA of' u 4 y n l by the crank yhandle 2, "willjfthen oause'the Fig. l. f

nism. Figs. 5 and'G are ldetail views illusthecrank vcase and the starter bracket respectively of the mechanism shown iny Fig. 1. Fig. 7 showsin longitudinal section, pafrt of a further modified construction.

According to the eXample shown in Figs. l, 2 and 3, -the power -shaft l of the starting mechanism carries at oneenda crank handle 2 which, as usual, is movableendwise thereon so as in this wayto become engaged there,- wit-h. The 'other end of the shaft is connected to the electric starting motor 3; Intermediately of its length, the power shaft l carries a vworm 4 that is adapted to slide en dways on a square or splined portion la of the said shaft, and which, in one position, namely that illustrated, herein-calledits forward position, engages witha worm wheel 6 secured,

l as by bolting to the fly wheel 7 of the engine,

or otherwiseV Xed to the engine crank shaft 8. The .worm 4 is thus movable ta'ngentially to the worm Wheel 7 6. f The sliding. of the Appication led rDecember 9, 1918. Serial No.` 265,918. .Y p

' moved in the opposite'or backward direction,

` Fig. 4 illustrates asimilar view to Fig. 1,-, showing another construction of the mecha` Speci-catonlof- Letters Iatent.j i

worm 4 in .the forwardldirection, -shown byf the arrow m, trom its engaged position, is pref vented b yan abutment which, in the example, Vis sho-wn `in the form 'ot acollar 9,"` connected 'by a pin Qa'to the shaft 1. `fWhen the shaft is shown bythe arrow g/,owingjto the engine worm 4 will move outof gearwith Athe'lYorin Y 'wheel 6., In its backward movement. ;the worm abutsagainstland movesfendw'ise along the power shaft'll', (a sleeve.lOthatieXtends towards thecrank handleQv. Thissleeve 10I is adapted to be 'moved in the other or fforward direction along the shatl by the forward end ways movement of thev hollowbossof the dle is so ormedinternally that when partly,-

turned into one lposition it can be moved'for. ward past the li1e;, o`n`the shaft with which the said boss is adapted toengage when the latter is i lafterwardsv moved backwardf partlyA rotated rinto another position.: 'Rotaftion of the power 'shaft' 1 by the motor 3, or

- crank handle 2 'alongtheshaft 1, itniayfbe worm 4to `gear with the 'worm wheel andv totr'avel into 'contactw'vfith:E the col'- Y -l'ar.9 before @starting 'or commencing to turn the worm wheel- .o'r startin' thebengin'e'. Bansin and 512?, Subject a ile pres-Smeer springsjl and mounted in a stationary bear` ing 1415er the power-Shaft I and'fsleevelO,

are adapted to 'engage'externalggroovesl s in thesleeve and thn's'to hold fthe. latterin either its vextreme backward or 'forward position, one'ofv the saidfballs, 'namely' the ball A12a also serving, bv engagement with a groove lin'the boss'of the worm,` to hold the. i

latter in its disconnected backward position clear of the wheelj. Ii`: th"e engine runs icc"A backward when being startedjiip, thepinrQa holding the" collar 9 'to' the powershaft L1, will besheared and the worm 4 will thejn be lthrown inl a `forward direction alongthe' j 1 vto aiiange 17 a connectedto .the rotor ofthe, electric motor 3 which may be arranged co, axially therewith. Meanssuch as a receptashaft in anl endwise direction.V The Aflanged ring 17 also serves to connect the power shaft cle 19 and duct 20, are or may-be provided forsupplying lubricant tothe teeth of the wormwheel. n.

In the example illustrated in Figs. 4, and 6, the worm 4 isiiXed to or formed on a hollow y horizontal power shaft 1 mounted to slide endways in stationary bearings 23, 24 carried by a frame or support 25. This frame or support also carries, at one end, altubular extension 26 of a bracketV orl casting 27 for an` electric motor 3 which is also arranged with its 'axis horizontal. VTo the left hand end portion of the power shaft 1 is Vfixed a ring 29, of V shape in section,- adapted .to coact with a spring controlled holding vdevice or detent 30 of similar shape in section lcarried in a holder 31 fixed to the frame or'supp'ort Thedetent 30l is adapted, when the power shaft 1 with its worm 4is moved into its backward or left, hand inoperative` posi tion, to yield in a downward direction' to ad- .Lio

mit of. the passage of the ring 29 on the shaft f and then to return andreta'in thefshaft in its inoperative position. Y Y

In this example the ring` 29 serves as the safety or yielding device for holding the hollow power shaft 1 and worm 4 in the in` termediate and operative position and to yield and allow the shaft and worm to be moved into the forward inoperative position by the worm wheel 6 when thisrwheel is driven in a backward direction by back ring or pre-ignition. For this purpose the ring 29 is adapted to .bear against the outer end of a bush 23a'held endways in thebearingh23, and is connected to the power shaft 1 by a pin 2,9?t that willbe sheared when theshaft and worm are forced forward bybackward rotation of the worm wheel 6.,

Intothe forward end `portion of the hollow power shaft 1 extendsy the rearward end'of a secondarypower shaft Y 32,'th'el vtwo shafts 1 and 32 being in driving Aconnection with each other by means, such as a headv 33 onthe sec` ondary shaft 32 'taking f into longitudinalV grooves 34 in the hollowshaft 1, so that vthe hollow power shaft can slideendways over the secondary shaft 32 and ybe .rotatedv by the latter shaft. The forward end of the secondary shaft'32 is provided with two cylindrical f enlargements 38 and 39 that are spaced apart as shown and are arranged to extend. into the' hollow lateral boss 40 of a toothedY driving wheel 41.; The vhollow boss ismounted IGO to rotate vin a forward bearing 24acarried by -theitubular extension 26 and is hcld-endwise in such bearing by the toothed driving wheel 41l bearingY against the forward end of the said 'bearing and by a ring 42-thatibears against the rear or opposite end of the bearing andV is litted to the secondary shaft 32 by a pin 43 that'passes transversely through it and the rear 'cylindrical enlargements 38 of the secondary shaft. The toothed driving v wheelv 41 is lingear withga toothed .pinion44 Yon therdriving shaft 45 of the electric motorV 3 and withV a toothed pinion 46.fix,flY j@Oone f end of aHshaft 47 the outer end of which car-V. Y

shaft in one direction only, in the usual way,

through a pin 49 on the shaft. The shaft 47 vries av crank'handle vadapted to drive vsuchfA A Y is arranged horizontally andcarried in bearings 27a in the bracket or casing 27 Icarrying the electric motor 3. In this arrangement the hollow power shaft 1 is adapted to be moved' forward byhand ,or otherwise to bring thev worm 4fthereony 'against the' worm wheelgG, and'to be rotated by hand by the crank handle 48, or by the electric motor 3, to-bringVV 'the worm 4. into gear with the worm wheel 6 andthe safet ring 29 against the bush 23zt to then enable t 'e worm' and worm wheely to be rotated by hand, or by .the'yelectric motor 3,V

to start the engine. lVhenthe lenginecomrear side of a ring 30 on one end of the shaft 1 with the spring controlled detent 30.

7 shows an arrangement in which the safetydevice is 'constituted by a spring controlled abutment device..y In the v.eX- ample shown, this abutment device comprises a piston Ofcarrying afball thrust 'de-V i' vice consisting of two rings v51 and V52 with interposed anti-friction balls 53. The pis-v ton .with ball thrust device VisV arranged` to slide in a cylinder54`rigidly.fixed tothe framework 25. The piston with ball thrust device is normally heldin the position shown againstarigid annular screw stop 55rv by a coiled spring 56. To the adjacent end of the shaft 1 is fixed' arcapyordiso 5,9'that is independent of the piston 50 and of the ring 52 against which it normally bears. The spring 56 is sufficiently compressed to ensure that the piston'with ballthrust device shall act as a rigid abutment forfthejshaft 1 through its cap or disc 59 so long as' the thrust of the shaft in the direction of the arrowAdoes not exceed'the normal amount requiredrto turnjtheworm wheel 6 intheI normal direction, shown the arrow` B, to turn the engine for starting in the normal running direction.' But 1n the'even't ofthe thrust ofthe shaft'in the direction A attaining an abnormalnvalue, due "to aback fire or other cause, tending to turn the engine in a direction contrary to the normalrota- 'tion-and thereby to turn the worm wheel 6 in thel vdirection 'offthe'arrow C, thenthe spring' 56- will 'become further compressed andallow the `worm 4 to move out of disengagement. with the )worm wheel G A spring `detent 57 serves,automatically, to prevent the return of thepiston 50 with ballthrust device 51-52-5'3, under the action of the spring 56, until such time as Vit Amay be released by withdrawing the detent' byhand.: 58 is another spring controlled detent adapted to engagewith-the cap'59` fixed to the adjacent end of the shaft 1, to prevent the rev-engagement of the worm 4 with the worm wheel 6 after the shaft 1 has been pushed to the right by the rotation of the worm wheel, when the engine has been started in the required normal direction of running.

, the means adopted to rotate the shaft lby electrical or manual power, the apparatus I may be constructed as in Figs. 4, 5 and 6.

In Fig. 7, the normal vdirection of turning ofthe worm wheel 6 is shown asv the reverse of that indicated, in Figs. land 4.

What I claim is l. EngineV starting mechanism comprising a worin wheel for connection to the driving shaft of an engine, a power shaft tangential to said worm wheel, bearings for said shaft, a worm carried by said power shaft and adapted to be moved into a forward operative position in gear with said worm wheel, into a backward inoperative position and also into a forward inoperative position, a

rigid stop'device connected to said shaft by Y a shear pin and serving normally to hold said worm in its forward operative position but capable of yielding by shearing the pin, to allow of said worm moving into its forward inoperative position when movedr in a :forward direction by said worm wheel .rotatingin a backward direction, and means for rotating said shaft.V n

2. For starting an internal combustion engine, mechanism comprising a worm wheel v for connection to an engine shaft, an end- Y ways movable power shaft arranged tangentially to said worm wheel, a woim fast ony said power shaft, bearings in which said power shaft can slide endways to move said worm into a backward inoperativeposition, into an intermediate position to bring said worin into operativeV connection with said worm wheel and into a forward position to admit of said worm occupying a forward inoperative position, means arranged external toone of said bearings and adapted normally to hold said power shaft in its intermediate position but capable of yielding when subjected to undue pressure and of then per- In other respects, as for example mitting said-..shaft anvd'worin to move into the forward inoperative positionand `means for rotating said power.shaft-,fandworm.` l

3. 'For starting an internalV combustion engine, 'aj worm wheel for connection? to, an

engine shaft,an endwaysmovable power4 vshaft' arranged tangentially 'to-said worin wheel, a 'worm fast on said shaft,bearings` i' y at oppositesi'des ofsad Worm in .which Said. Y. V75* shaft lcan slide-endways to'lmove saidworin intol av backward inoperative position, into an intermediate position lto bringv said worm -into operative connection with said' .worm

wheel 'and into'fa forward position'to admit of lsaid worm occupyingy a forward 1 inoperative position, means arranged external to one of said bearings` adapted'normally to hold said power shaftin its intermediate position but capable offyielding when subjected to undue pressure. and of thenper-k it kto be moved into its forward operative position by backward rotation of the worm wheel comprises a ring connected to the shaft i bya sha-fi; piny and arranged'to vbear against a fixed abutment when the shaft and worm are in the said intermediate and operative position but to yield when the shaft and worm are urged forward fromthat position by backward rotation-of the'worm wheel.

5. Engine starting mechanism accordingl f to claim 3, wherein there is combined with the driving means, a toothed driving wheel driven from the said driving means and provided .with a hollow lateral boss into which the secondary driving shaft extends, said wheel being in driving connection --with the driving shaftof said driving means.

6. Engine starting mechanism .accordingV nlV to claim 3, embodying a toothed driving wheel having a hollowlateral'boss, whereinA said boss is mounted to rotate in astation ary bearing and is prevented from moving axially therein in one direction by the said wheel' which is arranged to bear against one endl of the bearing, and from moving in the opposite direction by a ring vfixed to the secondary driving shaft and bearing againstV thevopposite end of the said bearing.

7. Engine starting mechanism according f to claim 3, whereinthere is associated 'witlr the secondary shaftand the motor, a toothed wheel driven by said driving means and con.v

viso

v nested to Said secondary shaft, av xed oasing vor support `provided with bearings, a

hand operated shaft mounted in said bear.- Vings with Lits axis parallel to the axis of the `'drivingmeans and a toothed wheel fixed'tov 'said hand operated Shaft and in gear with f .the toothed Wheel. driven by said driving starting .mechanisn'1-,- compris` ing'aworm Wheel vfor Connection to the drivingShaftof-an internal combustion engine,v anendvvays movable pov'verrshaft with v worm adapted to be moved by endwaysmotion of Said shaft into and out of gear With' saidgivorm Wheehbea'rngs forrsaid power shaft arranged at opposite/sides of said wor-m, a ring connected :to saidrvshaftv by a yieldingdeviee and adapted to bear. against -the outervside of one. ofsaid bearingsV when the Worm 1s in its operativeposltlon,'aseoondaryljshaft coaxialfwlthfthe power shaftV and in driving eonnectionwifh su'oh'jsl'aftj, I

a driving Wheel xed to said secondary shaft, a bearing for Said driving Wheel,V a 

